Nasal mask



FIG. 1 is a perspective view of a nasal mask showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is a second perspective view showing the nasal mask.

The broken lines in the drawings illustrate portions of the nasal mask that form part of the claimed design. 

CLAIM The ornamental design for a nasal mask, as shown and described. 